Usefulness of environmental DNA for Biomphalaria glabrata and Schistosoma mansoni surveillance and control of low schistosomiasis endemic areas in Brazil.

Schistosomiasis is a neglected parasitic disease that continues to affect hundreds of millions of people worldwide, particularly in developing countries. In Brazil, chemotherapy combined with access to safe water and improved sanitation has been effective in reducing the number of severe clinical cases. However, despite the current low endemicity, active transmission persists in several regions, where both infected individuals and the intermediate host, Biomphalaria glabrata, remain present. Therefore, more sensitive and scalable methods are needed to detect parasite dispersion and the presence of intermediate hosts in these areas. This study employed environmental DNA (eDNA) and real-time PCR (qPCR) to evaluate a molecular surveillance strategy for the detection of Schistosoma mansoni and B. glabrata in aquatic environments across municipalities in Minas Gerais, Brazil. Among 18 water sampling sites, S. mansoni and B. glabrata DNA were detected in 10 and 4 locations, respectively, with co-detection of both species in three municipalities. These findings highlight the potential of eDNA-based monitoring as a sensitive and non-invasive tool for environmental surveillance in low-endemicity settings. This approach can support more efficient management and control strategies for schistosomiasis.